Billy Tully, a washed-up boxer in Stockton, California, struggles with alcoholism and a sense of aimlessness following the end of his fighting career. During a training session at a local gym, Tully meets Ernie Munger, an enthusiastic teenager with potential. Tully encourages Ernie to pursue boxing and introduces him to his former manager, Ruben. Meanwhile, Tully finds himself entangled in a tumultuous relationship with Oma, a boozy barfly who adds chaos to his already unstable life.

As Ernie starts making strides in his boxing career, Tully attempts to turn his own life around by returning to the ring. He battles with physical and emotional hurdles as he seeks redemption and a sense of purpose. The movie explores themes of struggle, hope, and despair within the backdrop of the gritty world of small-time boxing. The journeys of both men intersect intermittently, showcasing their parallel battles with personal demons and the impact of their choices on their futures.